EA002961B1 - Detergent powder composition - Google Patents

Abstract

1. A process for the preparation of a granular detergent product comprising contacting a liquid binder component comprising an acid precursor of an anionic surfactant and a hydrotrope with a solid particulate starting material comprising a neutralising agent in a low shear mixer and granulating the mixture, wherein the hydrotrope is present at a level of at least 1% by weight of the acid precursor of the anionic surfactant and in which the acid precursor of the anionic surfactant and the hydrotrope are added substantially simultaneously to the mixer. 2. A process according to claim 1, in Which the acid precursor of the anionic surfactant and the hydrotrope are added as a single stream. 3. A process according to any preceding claim, in which the acid precursor of the anionic surfactant and the hydrotrope are at a temperature greater that 50 degree C when contacted with the solid starting material. 4. A process according to any preceding claim, in which the acid precursor of the anionic surfactant is a linear alkyl benzene sulphonic acid. 5. A process according to any preceding claim, in which the hydrotrope is para-toluene sulphonic acid. 6. A process according to any preceding claim, in which the neutralising agent is a water-soluble alkaline inorganic material. 7. A process according to claim 6, in which the neutralising agent is an alkali metal carbonate, bicarbonate or silicate. 8. A granular detergent product of bulk density in the range 450 to 800 g/l obtained according to claim 5.

Description

The present invention relates to granular detergents of low to medium bulk density, having excellent dissolution rates, flowability and particle size, and their preparation by the method of dry neutralization.

Background of the invention and prior art

Recently, the detergent industry has shown considerable interest in the industrial production of detergent powders with special bulk densities.

Usually, spray-dried detergent powders have a low bulk density, for example, 350-500 g / l, while powders obtained by conventional methods in non-tower type plants, in which the powders are dry mixed and, optionally, agglomerated, have high bulk density, for example, at least 700 g / l. Powders with intermediate bulk density, for example, in the range of 450-800 g / l, are obtained by mixing powders obtained by spray drying and dry mixing methods in appropriate combinations. However, the capital cost of such a method is very high, since the spray-drying method is capital-intensive.

The method of dry neutralization to obtain detergent powders is known in the art, but this method often results in powders with a high bulk density. 30 96/04359 (Ippueg) describes a method of dry neutralization to obtain a detergent powder of the desired bulk density, in which it is preferable to select the particle size distribution of the starting material or to introduce an additive for flowability. Indian Patent No. 166307 (Nsbiyap Leet) describes the specific use of an internal recirculating fluidized bed and mentions that using a conventional fluidized bed leads to the formation of a lumpy and sticky product.

Usually, hydrotropic substances that promote phase stabilization are used in liquid detergent compositions. US Patent No. 3,926,827 (Co1da1e-Pa1to1 | ye) describes hydrotropic substances as components that can hold oxygen bubbles, giving a greater volume of detergent.

95/23206 (Rtoter & Oatex) describes a method for the production of a detergent composition by preparing a paste that includes a surfactant system and a specific hydrotropic agent or mixture and has a detergent effect modifying agent, and their agglomeration. The specified composition has a bulk density of more than 650 g / l.

98/44084 (Deputier & Oatex) describes detergent particles, including an anionic surfactant and hydrotropic agent, for use in detergent compositions in order to provide an improved distribution of the composition. These particles are formed by spray drying a paste or suspension comprising an anionic surfactant.

EP-A-623 593 describes a process for the preparation of granular detergent particles, wherein the acid precursor of an anionic surfactant is neutralized with a solid neutralizing agent in the presence of a hydrotropic substance, which is predominantly a non-ionic surfactant. The method is characterized in that a high shear mixer is used.

30-A-99/00475 describes a method for producing a granular detergent with an average bulk density by neutralizing an acid precursor of an anionic surfactant containing a small percentage of an inorganic acid, with a solid neutralizing agent. There is no mention of using a hydrotropic substance in the method.

The main objective of the present invention is to develop not using spray drying method for obtaining granular detergent compositions with good powder properties and having a bulk density below 800, preferably below 700 g / l, more preferably below 650 g / l In particular, the detergent composition should have good dissolution rates, flowability and granulometry.

Another objective of the present invention is to develop a method of obtaining detergent compositions with an average bulk density, cost-effective compared with other conventional methods. It was found that the above objectives can be solved by dry neutralization of the acid precursor of the anionic surfactant with solid alkali in the presence of a hydrotropic agent such as p-toluenesulfonic acid.

Brief description of the invention

In accordance with a first aspect, the present invention provides a method for producing a granular detergent product, comprising bringing a liquid binder component containing an acidic precursor of an anionic surfactant and hydrotropic compound into contact with a solid, particulate starting material, including a neutralizing agent, in a mixer with low shear and granulation of the mixture, where the hydrotropic compound is present at a level of at least 1 wt.% from the acid precursor ika anionic surfactant, and wherein the acid precursor of an anionic surfactant and a hydrotrope compound is added to the mixer essentially concurrently.

According to a second aspect, the present invention provides a granular detergent product with a bulk density of between 450-800 g / l obtained by the method of the present invention.

Detailed Description of the Invention Definitions

Further, in the context of the present invention, the term granular detergent product encompasses commercial granular end products, as well as granular components or additional compounds to form the final products, for example, by postdosing to or with any other form of the mixture with additional components or additional compounds.

The granular detergent product, as defined herein, contains at least 5% by weight, preferably at least 10% by weight, of a synthetic anionic surfactant.

As used herein, the term powder means materials essentially consisting of particles of individual substances and mixtures of such particles. As used herein, the term granule means a small particle of agglomerated still smaller particles, for example agglomerated powder particles. The final product of the method according to the present invention consists of granules or includes a large percentage of granules. However, additional granular or powdered materials may optionally be added by postdosing to such a product.

According to the purpose of the present invention, the flow characteristics of the granulated product are defined in terms of the dynamic flow rate (ΌΕΚ - particle board), in ml / s, measured using the following procedure. A cylindrical glass tube with an inner diameter of 35 mm and a length of 600 mm is rigidly fixed along its longitudinal axis in a vertical position. Its lower end ends with a PVC cone having an internal angle of 15 ° and a lower outlet with a diameter of 22.5 mm. The first directional beam sensor is placed 150 mm above the outlet, and the second directional beam sensor is placed 250 mm above the first sensor.

To determine the dynamic flow rate, the outlet is temporarily closed and the cylinder is filled with granular detergent product up to the mark 10 cm above the upper sensor. The outlet opens and the expiration time 1 (seconds), necessary for the powder level to drop from the upper sensor to the lower sensor, is measured electronically. These measurements are repeated 2 or 3 times and take the average time. If the tube volume (ml) between the upper and lower sensors is designated as V, the particle board is expressed as ν / 1.

Except where otherwise indicated, values associated with powder characteristics, such as bulk density, are subject to the weathering granular detergent product.

Way

The method includes dry neutralizing the acidic precursor of the anionic surfactant with a solid neutralizing agent in the presence of a hydrotropic agent such as p-toluenesulfonic acid.

Low Shear Mixer

The method of the invention is carried out in a low shear mixer. Suitable low shear mixers for use in the method include rotating bowl mixers, drum mixers or concrete mixers. A low shear type gas fluidization mixer can also be used, which includes a fluidization zone where a liquid binder is sprayed onto the solid material.

Liquid binders can simply be injected into the mixer with a low shear or can be injected as a spray. The liquid binder is preferably injected into the mixer with a low shear.

In a preferred embodiment, the acid precursor of the anionic surfactant and the hydrotropic substance have a temperature above 50 ° C, preferably above 55 ° C, when fed into the mixer and brought into contact with the solid starting material. If other components are also present in the liquid binder, it is also preferable that these components are at a temperature above 50 ° C, preferably above 55 ° C, when fed to the mixer.

In a particularly preferred embodiment, the acid precursor anionic surfactant and hydrotropic substance are heated together to a temperature above 50 ° C. and then sprayed onto the solid starting material, preferably through the same nozzle, using a pump in a low shear mixer.

It has been found that in order to achieve the advantage of the invention, the acid precursor of the anionic surfactant and the hydrotropic substance should be added to the mixer with a low shearing force, essentially simultaneously. This can be done by introducing two components into the mixer at the same time, but with separate jets. However, it is much preferable that the two components are connected together before being fed into the mixer and fed in the form of a single jet.

Another important characteristic of the process is the addition of an acid precursor and a hydrotropic substance to a low shear mixer. Preferably, the rate and method of addition are such that the acid precursor is immediately consumed (neutralized) so that the acid precursor does not accumulate in the mixer in unreacted form. This also applies to hydrotropic agents, which are acids.

Liquid binder

The liquid binder includes an acidic anionic surfactant precursor and hydrotropic agent as major components.

The liquid acid precursor can be selected from linear alkyl benzene sulfonic (L8-LAS) acids, alpha olefin sulfonic acids, internal olefin sulfonic acids, fatty acid esters and sulfonic acids, alkyl sulfuric acids, fatty acids, and combinations thereof. The method of the invention is particularly useful for the preparation of compositions comprising alkyl benzene sulfonates by reacting an appropriate alkyl benzene sulfonic acid, for example the acid of AcPa from 8 Ps11. Linear or branched primary alkyl sulfates (PA8 PAS) with 10-15 carbon atoms can also be used.

Suitable hydrotropic substances that can be used for the process of the invention include para-toluenesulfonic acid, sulfylsuccinates, xylene sulfonates, cumensulfonates, and others known in the art. In a preferred embodiment, the hydrotropic substance is para-toluenesulfonic acid, either alone or as a mixture with another hydrotropic substance. References made here to para-toluenesulphonic acid also include its salts and in particular the sodium salt.

The content of the acid precursor anionic surfactant in the liquid binder can be as high as possible, for example, at least 98% by weight of the liquid binder, or it can be below 75% by weight, below 50% by weight. % or below 25 wt.%. Preferably it is at least 10 wt.%, More preferably, at least 25 wt.%, More preferably, at least 50 wt.%, Even more preferably, at least 75 wt.% And most preferably at least 90% by weight of the liquid binder.

The content of the hydrotropic substance in the liquid binder is at least 1, preferably at least 2.5, more preferably at least 5% by weight of the amount of acid precursor of the anionic surfactant present in the liquid binder.

In a preferred embodiment, the liquid binder essentially consists of an acid precursor of an anionic surfactant and a hydrotropic substance.

However, in addition to the acid precursor of the anionic surfactant and the hydrotropic substance, the liquid binder may include one or more other components of the granular detergent product. Suitable liquid components include anionic surfactants (i.e., neutralized salts), non-ionic surfactants, fatty acids, water, and organic solvents. The liquid binder may also include solid components dissolved or dispersed in the liquid component. The only limitation is that in the presence or in the absence of dissolved or dispersed solids, the liquid binder must be pumpable and can be delivered to a low shear mixer in a liquid, including paste-like form. Suitable anionic surfactants are well known to those skilled in the art. Examples of compounds suitable for incorporation into a liquid binder include alkyl benzene sulfonates, especially linear alkyl benzene sulfonates with a C ₈ -C ₁₅ alkyl chain length; primary and secondary alkyl sulfates, in particular C12-C15 primary alkyl sulfates; alkyl ether sulfates, olefin sulfonates; dialkyl sulfosuccinates and fatty acid ester sulfonates. Sodium salts are generally preferred.

If neutralized anionic surfactants are used in the liquid binder, it is highly desirable to obtain some or all of the anionic surfactants in place in the liquid binder by reacting an appropriate acid precursor and an alkaline compound, such as an alkali metal hydroxide, for example αΟΗ. Since the latter should usually be dosed as an aqueous solution, it inevitably includes some water. In addition, as a result of the interaction of an alkali metal hydroxide and an acid precursor, some water is also formed as a by-product.

However, in principle, any alkaline inorganic compound can be used for neutralization, but water-soluble alkaline inorganic substances are preferred. Another preferred compound is sodium carbonate, alone or in combination with one or more water-soluble inorganic substances, such as bicarbonate or sodium silicate.

Suitable non-ionic surfactants that can be included as a component of the liquid binder include one or more liquid non-ionic substances that are selected from ethoxylates of primary and secondary alcohols, in particular C ₈ -C ₂₀ aliphatic alcohols, ethoxylated on average 1-20 moles of ethylene oxide per mole of alcohol, and, mainly, C ₁₀ -C ₁₅ - primary and secondary aliphatic alcohols ethoxylated with an average of 1-10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated non-ionic surfactants include alkyl polyglycosides, glycerol monoethers and polyhydroxy amides (glucamide).

In a preferred embodiment, the liquid binder is substantially non-aqueous. In other words, the total amount of water inside it does not exceed 15% by weight of the liquid binder, preferably not more than 10% by weight. However, if necessary, a controlled amount of water may be added to facilitate neutralization.

Solid starting material

The solid starting materials of the present invention are particulate materials and can be powdered and / or granular. In addition to incorporating a neutralizing agent, the solid starting material may be any component of a granular detergent product, available in particulate form. Preferably, the solid starting material with which the liquid binder is mixed includes a modifying agent with detergent action.

In a preferred embodiment, the neutralizing agent is a water-soluble alkaline inorganic compound, preferably an alkali metal salt. Suitable neutralizing agents include carbonates, bicarbonates and alkali metal silicates, for example sodium salts. They can be used individually or in combination. Preferably, the neutralizing agent comprises sodium carbonate.

It is highly desirable to have a neutralizing agent in an amount sufficient to completely neutralize the acid component. Optionally, a stoichiometric excess of neutralizing agent can be used to ensure complete neutralization and / or provide an alternative function, for example, acting as a modifying agent with detergent action, for example, when the neutralizing agent includes sodium carbonate.

Product

The present invention also encompasses a granular detergent product obtained by the method of the invention (prior to any post-dosing or the like).

The granular detergent products of the invention have a bulk density of less than 800 g / l, preferably less than 750 g / l, more preferably less than 700 g / l, and most preferably less than 650 g / l. The bulk density can be as low as 450 g / l, however, preferably it is at least 500 g / l. It is preferably in the range of 450, more preferably from 500 g / l to below 700, more preferably 650 g / l.

Granular detergent products obtained by the method of the present invention have one or more improved powder characteristics. For example, granulated products have been found to have an improved dissolution rate, flowability, and grain size distribution.

A granular product is considered to be free-flowing if it has a particle board of at least 80 ml / s. Preferably, the granular products of the present invention have a particle board value of at least 80 ml / s, preferably at least 90 ml / s, more preferably at least 100 ml / s and most preferably at least 110 ml / s

Detergent compositions and ingredients

As indicated previously, the granular detergent product obtained by the method according to the invention may itself be a fully formulated detergent composition or it may be a component or additional substance that forms only a part of the specified composition. This section refers to a final, fully formulated detergent composition, unless specific disclaimers are given for the granular detergent product.

The total amount of the modifying additive with detergent action in the final detergent composition in accordance with the requirements is from 5 to 80 wt.%, Preferably from 5 to 60 wt.%, More preferably 10-35 wt.%. The modifying additive may be present as an adjunct to other components, or, if desired, modifying additive particles containing one or more materials of such an additive may be used separately.

In a preferred embodiment, the amount of material modifying additives included as part of a solid starting material consisting of particles, according to the method is such that the final content of the modifying additive in the composition is from 5 to 60 wt.%, Preferably 10-35 wt.% Of the granular washing product.

A preferred modifying agent is sodium carbonate, which may be the residue of an inorganic alkaline neutralizing agent used to form an anionic surfactant in place. Sodium carbonate, when present, is preferably 4-40% by weight of the final detergent composition.

Examples of other suitable modifying agents that may be present as a solid starting material or are subsequently mixed with a granular detergent product to obtain the final detergent compositions include crystalline or amorphous aluminosilicates, alkali metal sulfates and phosphates, and mixtures thereof.

Organic components, such as, for example, citrate, polyacrylates, etc., may also be present, as is obvious to those skilled in the art.

Granular detergent compositions may contain, in addition to anionic and / or non-ionic surface-active substances of the liquid binder, one or more other compounds with washing activity that can be selected from soap and non-soap anionic, cationic, non-ionic, amphoteric and zwitterionic surface-active substances and their mixtures. These compounds can be metered added at any appropriate stage before or during processing. Many suitable compounds with detergent activity are available and fully described in the literature, for example, in Sigle Asellus Ldepz apb South Africa. Secondly, 8th I, II, Lt. Zygap /, Repu-Aps Vegs.

Preferred compounds with detergent activity that can be used are soaps and synthetic non-soap anionic and non-ionic compounds.

Preferred detergent compositions of the invention include from 5 to 30% by weight of anionic surfactant, from 0 to 4% by weight of non-ionic surfactant, and from 0 to 5% by weight of fatty acid based soap.

The level of hydrotropic substances in the final detergent composition is from 0.25, preferably from 0.5, more preferably from 1 to 5 wt.%.

The detergent compositions may also contain a bleaching system, preferably a peroxide bleaching compound, for example, an inorganic persalt or organic peroxyacid, capable of forming hydrogen peroxide in an aqueous solution. The peroxy bleaching compound can be used in combination with a bleach activator (bleach precursor) to improve the bleaching effect at low wash temperatures. A particularly preferred whitening system comprises a peroxy-bleaching compound (preferably sodium percarbonate) optionally together with a bleach activator.

Usually, any bleaching and other sensitive ingredients, such as enzymes and flavors, are introduced by post-dosing after granulation along with other minor ingredients.

Typical minor ingredients include sodium silicate; silicates including corrosion inhibitors; anti-sedimentation agents such as cellulosic polymers; phosphors; inorganic salts, such as sodium sulfate; foam control agents or foam enhancers, respectively; proteolytic and lipolytic enzymes; dyes, agents to achieve a variegated color; flavors; foam controllers and fabric softeners. This list is not exhaustive.

Optional stratification agent or amplifier flowability can be introduced at any suitable stage of the method according to the invention. This improves the granularity of the product, for example, preventing aggregation and / or sintering of the granules. Any dissecting agent or flowability enhancer is usually present in an amount of from 0.1 to 15% by weight of the granulated product, and more preferably in an amount of from 0.5 to 5% by weight.

Suitable exfoliating agents / flow agents include crystalline or amorphous alkali metal silicates, aluminosilicates, including zeolites, citrates, Dikamol (P1sato1), calcite, diatomaceous earths, silica, for example, precipitated silica, chlorides, such as sodium chloride, sulfates, such as magnesium sulfate, carbonates, such as calcium carbonate, and phosphates, such as sodium tripolyphosphate. If desired, mixtures of these materials may be used.

Zeolite MAP is particularly useful as a dissecting agent. Layered silicates, such as 8K8-6 ex C1apai1, are also used as exfoliating agents.

The flowability of the powder can also be improved by including a small amount of an additional powder structurizer, for example, fatty acid (or fatty acid soap), sugar, acrylate polymer or acrylate / maleate, or sodium silicate, which is usually present in an amount of 1 to 5% by weight.

Typically, additional components may be included in the liquid binder or mixed with the solid starting material at an appropriate stage of the process. However, the solid components can be added post-dosing to the granular detergent product.

The granular detergent composition may also include a filler composed of particles (or any other component that does not contribute to the washing process), which typically includes an inorganic salt, such as sodium sulfate and sodium chloride. Na11 filler may be present at a level of from 5 to 70 wt.% From the granulated product.

The objects of the invention and its advantages are illustrated by the following non-limiting examples.

Examples

The method of obtaining the detergent composition

Granulated detergent composition of example 1 was obtained in the following way.

41.9 kg of the starting material, consisting of particles, containing sodium carbonate, sodium tripolyphosphate (8TPP-N'shF) and sodium chloride, were loaded into a mixer with a rotating tank. 10.4 kg of linear alkyl benzene sulfonic acid (LA8 - LAS), 1.5 kg of para-toluenesulfonic acid (PT8A - PTSK) and catalytic water were loaded into the chamber dosing unit. The specified liquid mixture was heated to 60 ° C with constant stirring. Then the liquid mixture was sprayed onto the particles in a mixer with a rotating tank through a nozzle with a multi-head. The contents were mixed for 60 seconds, allowing neutralization to complete. At the end, 0.9 kg of minor ingredients, such as anti-redeposition agents, phosphors, flow enhancers, were added and mixed for 20 seconds.

Examples A and B were prepared by the same method, except that in example A, PTSA was not added and the amount of water was adjusted respectively, and in example B, LAS and PTSA were added sequentially. In the example In addition, the PTSA was carried out after completing the addition of LAS to the same particles in a mixer with a rotating tank.

results

Various characteristics, such as bulk density, dissolution rate and dynamic flow rate of the compositions obtained on the basis of the compositions indicated in the table, are determined using standard test methods.

Example 1 Example BUT Example AT Components wt.% wt.% wt.% Linear alkylbenzenesulfonic acid 20 20 20 Modifying additives: sodium carbonate and NTPF 52 52 52 PTSK 2 2 Fillers 17 17 17 Background additives 6.8 6.8 6, 8 Water Up to 100% Up to 100% Up to 100% Specifications Bulk density, g / l 600 650 660 Dissolution rate,% 88 80 80 Dynamic flow rate 144 0 - very slow 0 - very slow

Detergent powder according to example 1 has much better flowability characteristics in comparison with examples A and B. In addition, the dissolution rate of the powder in example 1 is much higher than in examples A and B.

Claims (8)

CLAIM 1. A method for producing a granular detergent product, comprising bringing a liquid binder component containing an acidic anionic surfactant precursor and a hydrotropic compound into contact with a solid particulate starting material comprising a neutralizing agent in a low shear mixer and granulating the mixture in which the hydrotropic compound is present at a level of at least 1 wt.% of the acid precursor of the anionic surfactant, and in which ki lotny precursor of an anionic surfactant and hydrotrope are added to the mixer, substantially simultaneously. 2. The method according to claim 1, in which the acid precursor of the anionic surfactant and hydrotropic substance are added in a single stream. 3. The method according to any one of the preceding paragraphs, in which the acid precursor of the anionic surfactant and hydrotropic substance are at a temperature above 50 ° C when brought into contact with a solid source material. 4. The method according to any one of the preceding paragraphs, in which the acid precursor of the anionic surfactant is a linear alkylbenzenesulfonic acid. 5. The method according to any one of the preceding paragraphs, in which the hydrotropic substance is paratoluene sulfonic acid. 6. The method according to any one of the preceding paragraphs, in which the neutralizing agent is a water-soluble alkaline inorganic compound. 7. The method according to claim 6, in which the neutralizing agent is a carbonate, bicarbonate or alkali metal silicate. 8. Granular detergent product with a bulk density in the range from 450 to 800 g / l, obtained in accordance with the method according to claim 5.